The heating of parent metal prior to welding or cutting for the purpose of minimizing thermal shock and of slowing the cooling rate.

Related Links

What is Preheat?
Preheating can be critical to welding success
The Reasons for and Misconceptions about Preheating Steel
Why is preheat used when arc welding steel, and how is it applied? – TWI
What The Welding Inspector Should Know About Preheating And Postweld Heat Treatment

Related Videos